2. What is the significance of the Great Green Wall? Do Now:

3. Soil Resources Chapter 15 Chapter 15

4. Soils and their Preservation Soils and their Preservation

5. What is Soil? How Soils are Formed? –From parent material –Formation of 2.5 cm of topsoil requires time varies 200 – 1000 years –Depth varies (thin film, Poles, to 10 ft, forests )

6. What is Soil? What is Soil? The thin surface layer of the Earth’s crust consisting of:The thin surface layer of the Earth’s crust consisting of: minerals minerals organic matterorganic matter that has been modified by: WeatherWeather WindWind WaterWater OrganismsOrganisms

7. How Soils Are Formed How Soils Are Formed What three Weathering processes break parent material into smaller & smaller particles.What three Weathering processes break parent material into smaller & smaller particles.

8. How are Soils formed How are Soils formed Weathering processes break parent material into smaller & smaller particles.Weathering processes break parent material into smaller & smaller particles. –biological, chemical, & physical Respiring organisms give off CO 2 reacts in soil forming Carbonic Acid, H 2 CO 3Respiring organisms give off CO 2 reacts in soil forming Carbonic Acid, H 2 CO 3

9. Soil Topography Soil Topography Topography affects soil deposition.Topography affects soil deposition. –Steep slopes have little or no soil. –Weathering, Erosion, gravity, & runoff. –Slopes and valleys aid in soil formation & give rise to pioneer organisms.

10. Ecological Succession ClimaxCommunityPioneerOrganisms

11. Do Now: Do Now: What are some of the factors attributed to the everglades soil disappearing?What are some of the factors attributed to the everglades soil disappearing?

12. Everglades Disappearing Everglades Disappearing Everglade soil contains 15% or less of mineral particles and large amounts of organic matter.Everglade soil contains 15% or less of mineral particles and large amounts of organic matter. Organic material covered in water never really decomposed.Organic material covered in water never really decomposed. When organic material is exposed to oxygen it quickly decomposes…When organic material is exposed to oxygen it quickly decomposes… As the ground is drained, soil exposed to air and decomposition is accelerated.As the ground is drained, soil exposed to air and decomposition is accelerated.

13. Soil Composition Humus: a mixture of organic material that binds nutrient mineral ions and holds water.Humus: a mixture of organic material that binds nutrient mineral ions and holds water. Humus

14. What is Soil? Soil Composition 25% 45% 5% 25%

15. Soil Composition Soil Composition Litter: dead leaves/sticks, dung, dead remains of plants and animals.Litter: dead leaves/sticks, dung, dead remains of plants and animals. –Detritivores like Earthworms, termites, and ants help to breakdown humus. Humus: a mixture of organic material that binds nutrient mineral ions and holds water.Humus: a mixture of organic material that binds nutrient mineral ions and holds water. –Humus persists in agricultural soil for about 20 years. –Humus  CO 2 + H 2 O + nutrient minerals

16. Soil Pore spaces: Occupy about 50% of a soils volume and can be filled with H 2 OPore spaces: Occupy about 50% of a soils volume and can be filled with H 2 O (soil H 2 O) or air (soil air). Soil air is found in larger pores.Soil air is found in larger pores. Soil H 2 O is found in smaller pores (0.05mm).Soil H 2 O is found in smaller pores (0.05mm).

17. What is Soil? Soil Composition Other components: Pore space (wet soil) Pore space (dry soil)

18. Soil Water Leaching: the removal of dissolved materials from soil by the percolating of water downward.Leaching: the removal of dissolved materials from soil by the percolating of water downward. Illuviation: The deposition of leached material into lower layers of soil.Illuviation: The deposition of leached material into lower layers of soil. Illuvial materials include: Fe, & Al compounds, humus, and clay.Illuvial materials include: Fe, & Al compounds, humus, and clay.

19. Soil Air Contains less O 2 and more CO 2 compared to atmospheric air. (due to cellular respiration).Contains less O 2 and more CO 2 compared to atmospheric air. (due to cellular respiration).

20. What is Soil? Soil Horizons

21. Horizontal layers of organized soil.Horizontal layers of organized soil. A soil profile is a vertical section from surface to parent material.A soil profile is a vertical section from surface to parent material.

22. E-horizon develops if leaching is severe.

23. Soil Organisms Castings are produced ad digested soil passes through the intestine of an Earthworm.Castings are produced ad digested soil passes through the intestine of an Earthworm. Mycorrhizae: root fungus that lives in symbiosis with vascular plants (Tracheophytes). Mycorrhizae: root fungus that lives in symbiosis with vascular plants (Tracheophytes). Mycelium: threadlike body of the fungus that brings nutrients and water to the roots of the plant. In turn the fungus receives glucose from the plant via photosynthesis.Mycelium: threadlike body of the fungus that brings nutrients and water to the roots of the plant. In turn the fungus receives glucose from the plant via photosynthesis.

24. Earthworm Castings

25. ? ???????

26. Earthworm Dissection

27. Nutrient Cycling The pathways of various nutrient minerals or elements from the environment. Decomposition, assimilation, absorptionThe pathways of various nutrient minerals or elements from the environment. Decomposition, assimilation, absorption

28. ?

29. What is Soil? Nutrient Cycling (alternate slide) Organic matter in soil Decomposition Minerals freed and available to plant Plant roots absorb minerals from soil Elements incorporated into organic matter in plants Elements in organic matter in animals

30. Soil Texture The texture of a soil is determined by the percentages of particles like sand, silt, & clay that it contains.The texture of a soil is determined by the percentages of particles like sand, silt, & clay that it contains.

32. In soil, small particles (less than 0.002mm) are called?

33. Clay

34. Soil Properties and Major Soil Types Soil Texture: Sand, Silt, and Clay

35. Soil Ions Soil minerals are often present in charged versions called ions.Soil minerals are often present in charged versions called ions. Loam: an ideal agricultural soil that has an optimum combination of soil particle sizes.Loam: an ideal agricultural soil that has an optimum combination of soil particle sizes.

36. Soil Properties and Major Soil Types Availability of nutrient minerals in clay

37. Results of Negatively Charged Clay

38. Home work: This is “Black dirt” from Pine Island NY. –Yes that is it’s natural color! What can account for this significant difference in the physical and chemical nature of their soil?

39. Soil Properties and Major Soil Types Soil Properties Affected by Soil Texture

40. Soil Properties and Major Soil Types Soil Acidity pH scale 0 7 14 Most soils (pH = 4-8) Pygmy Forest Death Valley

41. Major Soil Types

42. Soil Groups Spodosols: have distinct layers (usually caused by colder climate, ample precipitation, & good drainage.Spodosols: have distinct layers (usually caused by colder climate, ample precipitation, & good drainage.

43. Soil Groups Alfisols: temperate deciduous forests produce this soil group. Brown to gray A- horizon, enough precipitation to wash clay and soluble nutrients into the B-horizon.Alfisols: temperate deciduous forests produce this soil group. Brown to gray A- horizon, enough precipitation to wash clay and soluble nutrients into the B-horizon. Maintained by detritus (leaf litter, twigs, acorn shells.Maintained by detritus (leaf litter, twigs, acorn shells. Fertile soilFertile soil

45. Aridosols Aridosols: desert and arid regions, hot and dry climates. Poor quality soil with specially adapted plant species.

46. Oxisols Oxisols: tropical rainforests, hot and wet climates. Poor quality soil due to mineral and nutrient storage within the rainforest organisms.

47. Dust Bowl ???????

48. Soil Problems Sustainable Soil Use: Wise use of soil resources, without a reduction in the amount or fertility of soil, So that it is productive for future generation

49. Soil Problems Soil Erosion Caused whean rainfall loosens particles water, wind, and ice transport away soil. Reduces the amount of soil which reduces soil fertility Sediment, flows into streams, rivers,and lakes affecting water quility and biotic habitats

50. Soil Problems Case-in-Point: The American Dust Bowl

51. Soil Problems Nutrient Mineral Depletion

52. Soil Problems, Dust Bowl Soil Problems in the United States Cultivated soils in southern Iowa, northern Missouri, western and southern Texas, & eastern Tennessee have greatest erosion 25% of agricultural lands lose more topsoil than formed

53. Soil Problems World Soil Problems Mineral depletion in tropical rainforest soils Degradation in the African Sahel

54. Soil Conservation and Regeneration Conservation Tillage

55. Soil Conservation and Regeneration Crop Rotation CORN 1 st Year SOYBEANS 2 nd Year OATS 3 rd Year ALFALFA 4 th Year

56. Soil Conservation and Regeneration Contour Plowing, Strip Cropping, and Terracing Strip cropping & contour plowing Terracing

57. Soil Conservation and Regeneration Preserving Soil Fertility Organic fertilizers e.g., manure, compost slow release, but nutrient content varies Commercial inorganic fertilizers e.g., typical bagged fertilizer exact nutrient content known, but prone to leaching

58. Soil Conservation and Regeneration Soil Reclamation increasing productivity on eroded land Shelterbelts